Sofa



FIG. 1 is a perspective view of a sofa showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a right side view thereof.

The longer dashed broken lines are for environmental purposes only and form no part of the claimed design. The shorter dashed broken lines depicting the stitching form part of the claimed design.

Views of the sofa not shown in the figures form no part of the claimed design. 

CLAIM The ornamental design for a sofa, as shown and described. 